University of Khartoum

Effect of Supplementation of Soymilk to Goat's Milk on the Chemical Composition and Sensory Characteristics of Yoghurt

Effect of Supplementation of Soymilk to Goat's Milk on the Chemical Composition and Sensory Characteristics of Yoghurt

Show full item record

Title: Effect of Supplementation of Soymilk to Goat's Milk on the Chemical Composition and Sensory Characteristics of Yoghurt
Author: Igbal Mohamed, Abd El Haleem
Abstract: This investigation was carried out to study the effect of supplementation of goat's milk with soymilk and the addition of gum arabic and fruit juices on the quality of yoghurt. Yoghurt was made from fresh goat's milk supplemented with soymilk (10, 15 and 20%), mixed with gum arabic (0.5 and 0.7%), sugar (6%) and juices of banana (90 mg/l00 ml water), mango (50 mg/l00 ml water) and guava (100 mg/l00 ml water) plus the control sample (made from fresh goat's milk). The starter culture was added at the rate of 3% (w/w) (a combination of Streptococcus thermopiles and Lactobacillus burglaricus at 1: 1 ratio). Yoghurt was manufactured and stored at 4°C for 6 days. Chemical composition (fat, protein, total solids and ash contents and titratable acidity) and sensory characteristics (color, flavor, consistency, taste and overall acceptability) were determined at 0, 3 and 6 days intervals. The results showed that fat, protein and ash contents and acidity were high (3.67±0.17, 7.51±0.82, 0.68±0.08 and 1.12±0.02, respectively) in the plain yoghurt, while the highest value of total solids was obtained in yoghurt supplemented with 10% soymilk (18.65±1.34). The lowest values of protein, ash and acidity were obtained in yoghurt supplemented with 20% soymilk (6.20±1.17, 0.52±0.10 and 0.89±0.14, respectively). The lowest value of fat was obtained in yoghurt supplemented with 15% soymilk (2.89±0.46). The highest scores of color, flavor, consistency and overall acceptability were obtained in the plain yoghurt (4.80±0.66, 3.53±0.90, 3.23±l.19 and 3.70±l.53, respectively), while the highest score of taste was obtained in yoghurt supplemented with 15% soymilk (3.53±l.05). The lowest scores of color and taste were obtained in yoghurt with 20% soymilk (3, 53± l.25 and 3.31±l.17, respectively), while the lowest scores of flavor and overall acceptability were obtained in yoghurt with 10% soymilk (2.27±0.86 and 3.41±l.18, respectively). The addition of fruits affected the quality of yoghurt, and the results showed that the highest values of fat, protein, ash and acidity were obtained in the plain yoghurt (3.67±0.16, 7.51±0.82, 0.68±0.08 and 1.12±0.02, respectively), The highest value of total solids was found in guava yoghurt (19.38±0.92). The lowest values of fat, protein and ash were obtained in mango yoghurt (2.95±0.89, 5.84±0.74 and 0.55±0.12, respectively), while the lowest value of acidity was obtained in guava yoghurt (0.81±0.15). The highest score of taste was obtained in the plain yoghurt (3.50±l.72). The lowest scores of color, taste and overall acceptability were obtained in banana yoghurt (3.21±l.25, 3.37±l.20 and 3.37±l.16, respectively, while the lowest score of flavor (2.28±0.83) and consistency (2.67±0.97) were obtained in guava and mango yoghurt, respectively. The results showed that concentration of gum arabic affected the quality of yoghurt, with the highest content of fat, protein, ash and acidity being obtained from the plain yoghurt, while the highest value of total solids (14.88) was found in yoghurt with 0.5% gum arabic. The lowest values of protein (6.35%), ash (0.57%) and acidity (0.89%) were obtained in yoghurt with 0.7% gum arabic. The highest scores of color, flavor, consistency, taste and overall acceptability were obtained in the plain yoghurt, while the lowest scores of color (3.59±0.181), flavor (2.35±0.83), taste (3.38±l.19) and overall acceptability (3.45±l.09) were obtained in yoghurt with 0.5% gum arabic, and the lowest score of consistency (2.73±0.99) was obtained in yoghurt with 0.7% gum arabic. The highest values of fat (3.19:±0.58), total solids (17.74±2.43) and ash (0.64±0.10) were reported at the 3rd day of storage period, while the highest values of protein (6.93±l.25) and acidity (0.96±0.17) were obtained at the 6th day of storage. The lowest values of fat (3.13±0.46), protein (6.22±0.94) and acidity (0.98±0.18) were obtained at the beginning of storage period, while the lowest values of ash (0.58±0.11) and total solids (16.95±2.05) were obtained at the 6th day of storage period.. The highest scores of color (3.94±l.17), consistency (3.01±l.02), taste (3.64±l.06) and overall acceptability (3.72:±0.98) were reported at the 3rd day of storage, while the highest score of flavor (2.63±0.76) was obtained at the 6th day of storage. The lowest scores of flavor (2.17±0.88), consistency (2.45±l.0l) and overall acceptability (3.70±l.07) were reported at the beginning of storage period, while he lowest scores of color (3.16:±l.22) and taste (3.06±l.26) were obtained at the 6th day of storage period.
URI: http://khartoumspace.uofk.edu/handle/123456789/14363
Date: 2015-06-23


Files in this item

Files Size Format View

This item appears in the following Collection(s)

Show full item record

Share

Search DSpace


Browse

My Account